In the automotive sector, cable harnesses are often wrapped with adhesive tape, wherein mainly textile adhesive tapes have assumed numerous additional functions, such as protecting the cables from abrasion or damping of valve or vibration noise, apart from the pure bundling function.
As an alternative to helical wrapping of cable sets, today numerous systems of longitudinal sheathing are offered, wherein at least in part adhesive tapes find application as sheathing of the above-named type. For instance, DE 295 10 907 U1 describes an inner-side adhesive cable jacket with laterally projecting closure; DE 196 11 586 A1 a foil sleeve with one-sided, non-projecting adhesive closure; EP 1 000 127 B1 full-surface adhesive products for longitudinal sheathing; EP 1 312 097 B1 and EP 1 300 452 B1 sleeves with in each case at least one narrow, laterally projecting closure adhesive tape strip; DE 102 02 454 A1 a sheath made from two separate tapes, of which at least one is an adhesive tape; EP 1 723 210 B1 a double-layer abrasion protection tape suitable for longitudinal adhesion; EP 1 739 148 A2 a sleeve with outer-side adhesive; and EP 2 034 576 A2 a double-layer sleeve with two adhesive lateral strips. Of the above-named products, especially those that have a largely adhesive-free inner side are advantageous in the manufacture of highly flexible sheaths for large cable-set diameters. This is referenced for example in the cited EP 1 315 781 B1, wherein an inner-side adhesive-free helical wrapping is described.
In order to be able to lay the possibly already sheathed cable sets in a machine or an automobile in a defined manner, they must be fastened to the body. As a rule this is done with clips that are attached to the cable set, which for their part are inserted in bores in the body. These clips are fastened to the cable set in a known manner by two additional wrappings of narrow adhesive tape. This is comparatively expensive and also brings with it the danger of so-called flagging, that is, that the ends of the adhesive tape become detached due to incorrect installation and protrude from the sheathing.
It is the object of the present invention to provide a sheathing of the above-named type, which on the one hand fulfills the function of the sheathing, and at the same time on the other hand both assures a fastening performable with reduced effort during installation of the encased product, and effectively prevents detachment of the adhesive tape ends in the installed state.
According to the invention this is achieved in that there is at least one hole in each edge region of the sheathing, wherein one hole in the one edge region is respectively associated with one hole in the other edge region in such a way that the holes can be caused to coincide with one another due to folding of the carrier along or parallel to a main axis extending through the middle region of the carrier or due to bending or flexing of the carrier about an axis spaced from the carrier extending parallel to this main access.
Due to this invention a sheathing of the elongated product is thus advantageously created that simultaneously offers the possibility of fastening of the product to be sheathed or already sheathed with minimal effort, in particular of cable sets in automobile manufacture. Clips or similar fastening, such as, for example, those needed for fastening of cable sets in an automobile body, which up until now were wrapped in an expensive manner separately on a possibly already sheathed cable harness, can now advantageously be directly integrated according to the invention into the sheathing, by being routed through prepared holes, initially through one of the holes in the one edge region and then during installation through the corresponding hole in the other edge region, so that in the installed state in each case a clip is run through a pair of holes associated with each other.
The invention can therefore be used advantageously both for manufacture of longer sleeves, wherein the function of protection of the product to be sheathed plays a significant role, as well as for short sheathing that serves only for fastening, which can also be designated as clamps and will be so designated hereinafter.
A further advantage of the invention consists in that it can be combined with all of the above-mentioned presently offered diverse known systems for longitudinal sheathing, wherein the sheathing according to the invention preferably can be configured as an adhesive tape—at least as a tape that is adhesive in sections. Preferably here a full-surface or discontinuous adhesive layer consisting of a pressure-sensitive adhesive can be used at least on one side.
Since the combinable fastener for fastening to the sheathing according to the invention in the envisioned manner, in particular the clips, if they are not spaced too far apart, can simultaneously be used for closure of the sheathing, it is possible in a specific embodiment to dispense entirely with the closing effect of an adhesive layer in a sheathing according to the invention.
Hence with use of a largely adhesive-free inner side, there is a possibility of manufacturing highly flexible sheathing both for small as well as for large cable-set diameters. For simple fitting of the sheathing according to the invention to various diameters of the elongated product, it can be advantageously provided that at least one of the holes forming the pair is designed as an elongated hole, or that a hole in the one edge region is associated with a plurality of mutually offset holes in the other edge region, so that using a clip, a belt-like closure of the sheathing is made possible.
It is also possible to use various embodiments of strip-layered carrier materials when these are provided with holes according to the invention through which the clips required for fastening can be inserted. In particular, exclusively lateral fastening lugs optionally present on the fastener according to the invention can advantageously be provided with the adhesive layer.
It can universally be used with textile adhesive tapes, foil-adhesive tapes and/or adhesive tapes with a backing, the invention permits further desired additional functions to be imparted, according to the existing demand profile, to a sheathing according to the invention in addition to the bundling function and the fastening function. Various properties such as temperature resistance, abrasion protection, or noise damping may be in the foreground.
For determination of suitability for a specific demand profile, testing of adhesive tapes for wrapping of cable sets in the automobile industry usually is carried out in accordance with comprehensive standards, as summarized for example in LV 312 (1/2009-LV312-1 regarding adhesive tapes; LV 312-2 regarding longitudinal sheathings) as joint testing guidelines of the firms Audi, BMW, DC, and VW.
Thus regarding thermal resistance, in LV 312 the classification in Table 1 below is provided.
TABLE 1Temperature classes according to LV 312Continuous serviceShort-termTemperature fortemperature,temperaturethermal overloadClassTU to TO in ° C.(TO + 25) ° c.(TO + 50) ° C.A−40 to 85 110 ± 2135 ± 3B−40 to 100125 ± 3150 ± 3C−40 to 125150 ± 3175 ± 3D−40 to 150175 ± 3200 ± 3
In addition, the division into various temperature classes is made on the one hand according to LV 312 based on their compatibility with different wiring, while on the other hand consideration is given to the closure tightness of the protective system at elevated temperatures. The latter is substantially improved by the invention by the presence of fastening inserted through the holes.
When UV cross-linked acrylate adhesives with high temperature resistance are used as the pressure-sensitive adhesive in the adhesive layer for the elongated product in the context of the invention, sheathing can be obtained that can be used under normal bending stress, that is in particular for a bending stress that occurs when cable sets are laid in an automobile, up to temperature class D according to Table 1 above. In principle, however, the use of rubber-based adhesives is also possible when only a lower temperature resistance is required.
Also as regards noise damping behavior, LV 312 for cable protection systems, as they can be provided by the sheathing according to the invention, provides for classification into five classes. These are reproduced in Table 2 below.
TABLE 2Noise damping classes according to LV 312Noise damping classRequirementA—no noise damping0 to 2dB (A)B—slight noise damping>2 to 5dB (A)C—medium noise damping>5 to 10dB (A)D—high noise damping>10 to 15dB (A)E—very high noise damping>15dB (A)
Using a suitable carrier design, for example by using fleece materials in the carrier, which may also possibly be designed two-layer or multi-layer, it is possible that a sheathing produced with a sheathing according to the invention can achieve at least the noise reduction class C, preferably even class D according to LV 312.
As regards abrasion resistance, LV 312 provides the classification shown in Table 3 below. Here a mandrel with a diameter of 5 mm is used for testing.
TABLE 3Abrasion classes according to LV 312RequirementAbrasion class(number of strokes)A—no abrasion protection  <100B—slight abrasion protection100-499C—medium abrasion protection500-999D—high abrasion protection1000-4999E—very high abrasion protection 5000-14999F—extremely high abrasion protection15000-29999G—abrasion protection for special applications≥30000
Selection of the suitable design as well as suitable materials for the carrier, which for example can preferably be comprised of a fabric made from polyethylene terephthalate (PET) or polyamide (PA), can ensure that a sheathing according to the invention can achieve at least abrasion class C, preferably class D according to LV 312.
As further tests of importance in application technology, the described guideline, which in particular has the nature of a delivery specification or standard, for example testing methods are also described for the compatibility of adhesive tapes with electrical automotive wiring, as well as for chemical resistance, fogging and flagging behavior, and radiant heat protection.
Due to the possibility of dispensing with the use of the additional narrow closure strips or the use of additional adhesive tape with the known wide sleeve sheathing, with a sheathing according to the invention, not only is simpler manufacture possible, but the sheathing material also assures improved strength of the closure.
In sheathing according to the invention with special suitability required for radiant heat protection, a backing with at least one backing layer that is comprised of a metal material can preferably be used without negative effects with regard to the ends of the sheathing material possibly protruding after installation.